Can Spam For Good

Because spam changes constantly, spam filters must change too. Bayesian filters (the type of filter used in Apple Mail) learn to identify spam by evaluating how often certain words occur in spam messages. For example, if you mark most messages that contain the word “mortgage” as spam, the filter learns that similar messages should go to the Junk folder.

Of course, this ability to learn is dependent on the user’s willingness to teach. Training mail filters by marking any unidentified spam is most critical during the first several weeks, but the process should never really end. Also important is to correct any false positives—those good messages that your filter mistakes for spam. If you’re using Mail’s built-in filter, press Command-Shift-J to mark or unmark the selected message as junk. When Mail is correctly identifying most junk messages, click Mail > Preferences, select the Junk Mail tab, and check the option to automatically move junk messages to the Junk mailbox.

Like young Jedis being trained in the ways of the Force, modern mail filters must be trained in the ways of blocking spam.

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5. Upgrade Mail’s Spam Filter

For heavy email users, Mail’s built-in spam filter may not be enough. Our favorite replacement is SpamSieve ($30). Like Apple Mail, SpamSieve employs a Bayesian filter that learns what you consider spam and adapts as new types of spam arrive. The difference is hardiness and aptitude - within two days SpamSieve was trapping spam that had eluded Mail for months. The program integrates nicely with Mail, adding its own group of menu items and keyboard shortcuts for marking messages as good or junk. A full-featured demo is available free for 30 days. After a week of training, the difference in our inbox was hard to believe.

SpamSieve records its successes and failures, making it easy for you to judge its effectiveness.